Delete a custom field definition
Authorizations
A secret API key. Publishable keys cannot reach this API. A key may carry an expiry, and an expired key is refused exactly like an unknown one, with a 401 that names no reason; check the key's expires_at in the dashboard rather than inferring it from a response. When a merchant rolls a key's secret they choose a grace window of up to 3 days, and for its duration BOTH the new secret and the one it replaced authenticate, so an integration moves over on its own deploy schedule instead of at the instant the button is pressed. Move before the window closes: after it, the old secret is refused. Nothing else about this contract moves with a roll. The key keeps its id and its scopes, so the only thing an integration updates is the credential itself.
Headers
A unique key per logical write. Replaying a request with the same key returns the first response byte for byte instead of applying the write twice.
Path Parameters
Body
Takes no parameters, and an empty body is expected. IT REFUSES WHEN THE DEFINITION IS IN USE, with 409 definition_in_use and the number of values still stored under it. A definition delete CASCADES: removing one erases that field from every product, order and customer that carried a value, in a single request whose URL names none of them. Clear them with DELETE /api/v1/metafields/{metafieldId} first, so the intent is explicit in what you did rather than inferred from one call. REQUIRES write_metafields:delete in addition to write_metafields, for the same reason: correcting a field's label and erasing the data stored under it are different acts, and a merchant must be able to grant the first without granting the second. A definition that is already gone is a 404 rather than a 204. A fresh Idempotency-Key against a missing id means you believe something is there, and answering 204 would read as a removal that never happened; a REPLAYED key still returns the stored 204, because that retry did land.
Response
Success. The response has no body.